1. Field of the Invention
The present invention relates to displaying graphical information on a display device and in particular to controlling the display of different subsets of graphical information.
2. Brief Description of Related Developments
Although the development of digital computing devices and storage devices during previous several decades has resulted in devices capable of very high speed processing and very large storage capacity, there still remain problems to solve with respect to interfacing with users of the devices. One example of such a problem is that of how to provide for a user to easily view large documents, such as a word processor or spread sheet document having hundreds of pages or a web page having thousands of lines of text and images. In particular, editing and browsing a large word processing document is usually very cumbersome when the user needs to refer to many different parts of the documents.
For example, while editing the document at a first position within the document the user may need to copy a paragraph of text from another part of the document. When performing this operation, the user will have to perform a first scrolling operation to scroll the document within a window on the display screen of the computer, thereby removing the current part of the document from view, and then perform a copy or cut operation. This is then followed by a second scrolling operation in order to bring the current position into view again. When performing this second scrolling operation, the user will typically have to concentrate on studying the content of the scrolling window in order to recognize the position in the document, i.e. the current position, where to stop the scrolling operation. This is a problem at least in two aspects, since it requires the user to be very attentive to the scrolling content of the window, which also means that the scrolling may take an unnecessarily long time to perform.
State of the art solutions to this problem are very simple and hence do not compensate for the inconvenience of having to watch and study scrolling content in a display window. For example, word processors and spread sheet applications usually provide the user with a dynamic page number indicator that, during scrolling operations, display a numeral representing a page number or a line number.